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At least 19 recordsLinked to original sources

PubMed1975

Excretion of 2-hydroxyestrone in urine throughout human pregnancies.

Urinary 2-hydroxyesterone was quantitatively determined in the course of several normal human pregnancies. The urine was subjected to hot acid hydrolysis and after chromatographic purification, 2-hydroxyesterone was converted into the corresponding phenazine derivative, which was submitted to a final column chromatogrphy and then quantitated by UV-spectrometry. For correction of procedural losses 2-hydroxyestrone-4-14C was used as internal standard. The urinary 2-hydroxyestrone of different subjects varied within a wide range especially at mid-pregnancy between 100 and 2500 mug/24 h. The day-to-day variation of the excretion of 2-hydroxyestrone was mostly less than 30% of the total value of that day, but sometimes could even reach 60%. The investigation of 2-hydroxyestrone and total estrogens at regular intervals throughout several pregnancies, showed that the excretion of 2-hydroxyesterone generally reached a maximum during the second trimester, while the excretion of the total estrogens steadily increased up to parturition. When analyzing the urines of different subjects during the last 4 months of pregnancy, no correlation appeared to exist for the excretions of the total estrogens and of 2-hydroxyestrone.

Adult↗

PubMed1978

Radioimmunoassay of 2-hydroxyestrone.

Under the protection of ascorbic acid a 2-hydroxyestrone bovine serum albumin conjugate was prepared containing intact 2-hydroxyestrone as determined by gas chromatographymass spectometry. Using this antigen highely specific antibodies were raised in rabbits. Cross-reactivity for 2-hydroxyestradiol and 2-hydroxyestriol was 26 and 4.5%, respectively. An assay procedure of 2-hydroxyestrone in human plasma is described. Using special precautions the assay allows the determination of 2-hydroxyestrone in plasma samples of women (50-95 pg/ml), pregnant women (105-220 pg/ml), men (45-65 pg/ml) and children(20-40 pg/ml).

Adult↗

PubMedDate not supplied

Radioimmunoassay of 16 alpha-hydroxyestrone in human urine.

A radioimmunoassay for the quantitation of the sum of free, glucuronidated and urine is described. The method is reliable and accurate. Using this method, urinary excretion of 16 alpha-hydroxyestrone was determined in normal men, premenopausal women, and postmenopausal women. The values were compared to the urinary excretion of estrone and estradiol. In two women, the urinary excretion of the three estrogens was measured in daily samples throughout a normal menstrual cycle. We conclude that 16 alpha-hydroxyestrone is a quantitatively important urinary estrogen. Inclusion of the measurement of 16 alpha-hydroxyestrone should yield a more accurate assessment of estrogen metabolism.

Estradiol↗

PubMed1991

Temporal relationships among the excretory patterns of 2-hydroxyestrone, estrone, estradiol, and progesterone during pregnancy in the rat.

The urinary excretion pattern of 2-hydroxyestrone, estradiol, estrone, and progesterone was examined in rats during early, mid, and late pregnancy. Progesterone increased from early to mid pregnancy and declined significantly 2 to 3 days prior to parturition, corresponding to changes observed in blood levels by others. 2-Hydroxyestrone, the major estrogen in rat urine, increased significantly 4 days prior to delivery and remained elevated until it further increased sharply the day of parturition. Urinary estradiol and estrone levels showed little change until the day of parturition, when they increased significantly. Multiple correlation analysis of the data implied that 2-hydroxyestrone and estradiol were negatively correlated at the time of implantation. The results suggest that catechol estrogens, through their effect on prostaglandin synthesis, may participate in the process of implantation as well as in the mechanism involved in the onset of labor.

Animals↗

PubMed1991

Structure of the adduct of 16 alpha-hydroxyestrone with a primary amine: evidence for the Heyns rearrangement of steroidal D-ring alpha-hydroxyimines.

16 alpha-Hydroxyestrone, a product of estrogen 16 alpha-hydroxylation in humans that is suspected to be implicated in cell transformation, has been found to form stable adducts with nuclear components. The stable covalent adduct formed from 16 alpha-hydroxyestrone with 2-methoxyethylamine via the Heyns rearrangement of the alpha-hydroxyimine was identified as 3-hydroxy-17 beta-(2-methoxyethylamino)estra-1,3,5(10)-trien-16-one. Since the same product was obtained from 16 beta-hydroxyestrone with the amine, the alpha-hydroxyenamine is the most likely intermediate of the Heyns rearrangement. The adduct was fairly stable at 37 C in phosphate buffer (pH 7.4)/methanol (1:1 v/v), while the adduct formed from 16-oxoestradiol was disrupted reversely and completely within 6 hours. The evidence suggests that N-(3-hydroxy-16-oxoestra-1,3,5(10-trien-17 beta-yl)amine is the partial structure of the stable adducts formed from D-ring alpha-ketol estrogens with proteins.

Amines↗

PubMed1990

In vitro synthesis of 16 alpha-hydroxyestrone by female rat liver microsomes: its possible role in the etiology of breast cancer.

Liver homogenates from female rat strains (Sprague-Dawley, Wistar and Fisher) were incubated in a NADPH regenerating medium in the presence of labelled and unlabelled estrone. Liver microsomes isolated from male rats and female mice were used as positive controls. Using HPLC and paper chromatography, under the experimental conditions used it was found that liver homogenates from female rats were able to convert estrone to various metabolites such as 16 alpha-hydroxyestrone. In a mutagenicity assay (Ames test), with 16 alpha-hydroxyesterone as test substance, two strains (TA98 and TA1538) of the five strains tested showed a 2-3-fold increase in the number of his+ revertants relative to the control values. Estrone did not cause any mutagens in the test used. It is concluded that female rats are able to synthesize 16 alpha-hydroxyestron in vitro. Whether this compound is risk factor for breast cancer remains unclear.

Animals↗

PubMed1979

Absence of measurable 2-hydroxyestrone in the rat brain: evidence for rapid turnover.

The free 2-hydroxyestrone content of female rat brains was measured by two independent methods, including a direct radioimmunoassay and enzymatic conversion to stable O-methylated derivatives followed by a specific radioimmunoassay for the latter. The sensitivities of the two procedures were 10 pg and 5 pg respectively and the recoveries were greater than 85%. Neither assay method was able to detect any measurable endogenous 2-hydroxyestrone in the female rat brain at any stage of the ovulatory cycle. It is suggested that a high turnover rate of 2-hydroxyestrogens in the rat brain precludes the accumulation of detectable quantities of these metabolites in central tissues.

Animals↗

PubMed1975

The excretion of 2-hydroxyestrone during the menstrual cycle.

A double isotope derivative determination technique was developed to investigate the excretion of 2-hydroxyestrone inhuman menstrual cycle. The method is highly specific, accurate and precise within the range of 0.2-20 nmol 2-hydroxyestrone/20ml of urine. The amounts of 2-hydroxyestrone excreted during menstrual cycle varied between 10 (proliferation phase) and 60 mug/24 h urine (ovulatory peak), which is comparable to that of estriol, supposed hitherto to be the main excretion product of estrogen metabolism.

Estrone↗

PubMed1975

[Excretion of estriol, estetrol, 16-epi-estriol, 16-keto-estradiol and 16-hydroxyestrone in the 24-hour urine of pregnant women in the last trimester].

In this publication a method is given which allows simultaneous estimation of estriol, estetrol, 16-epiestriol, 16-ketoestradiol and 16-hydroxyestrone in urine of pregnant women. First conjugates are precipitated with ammoniumsulfate and hydrolyzed. Then the steroids are extracted and converted to azodyes by reacting with the diazonium salt dark blue r. After separation by thin layer chromatography the azodyes are measured by remission analysis with a chromatogramm spectrophotometer. From the data obtained from 66 cases norm groups were set up for the excretion of the steroids in the 3rd trimester of pregnancy. In the last month of pregnancy the average excretion, expressed in % of excreted estriol, is as follows: estetrol 5,7%, 16-epiestriol 3,1%, 16-ketoestradiol 7,0%, 16-hydroxyestrone 5,3%.

Adult↗

PubMed1985

Determination of 16 alpha-hydroxyestrone by radioimmunoassay in systemic lupus erythematosus.

A radioimmunoassay for the feminizing metabolite 16 alpha-hydroxyestrone was applied to a variety of sera from healthy volunteers, patients with active or inactive systemic lupus erythematosus (SLE), and patients with other rheumatic diseases. A significant increase in this metabolite was detected in patients with SLE, especially those with active disease, compared with normal controls (P less than 0.001). SLE patients were categorized as having either active or inactive disease by clinical and laboratory criteria. Many patients who had clinically and serologically active disease were found to have normal levels of this estrogenic metabolite, and several explanations for these differences are explored in this report. Despite a poor correlation of hormone levels with age, antibody levels, or complement levels in patients with SLE, those patients with the highest levels of hormone were among those whose disease was clinically most active.

Adult↗

PubMed1987

Inhibition of the preovulatory LH surge after a catecholestrogen (2-hydroxyestrone) antiserum injection in the third ventricle of cycling female rats.

Administration of a catecholestrogen (2-hydroxyestrone, 2-OHE1) antiserum (2-OHE1-AS) in the third ventricle of cycling female rats, on the morning of proestrus, leads to a significant reduction in the afternoon LH surge. These responses are dose-dependent and can be observed even when the 2-OHE1-AS is injected on the diestrus morning. Almost similar results were obtained with an antiserum against 17 beta-estradiol (17 beta-E2). Nevertheless, the fact that the central immunoneutralization of 2-OHE1 impedes the preovulatory surge of LH at a time of high peripheral levels of 17 beta-E2 strengthens the idea of a specific role for 2-OHE1 in the control of cycling LH release.

Animals↗

PubMed1985

Interaction of histones with estrogens. Covalent adduct formation with 16 alpha-hydroxyestrone.

Disturbed estrogen metabolism leading to increased 16 alpha-hydroxyestrone (16 alpha-OHE) has been described in patients with systemic lupus erythematosus and mammary carcinoma. Previous studies showed the formation of covalent complexes between 16 alpha-OHE and nonspecific cellular membrane proteins. The present study is concerned with the interaction of 16 alpha-OHE and histones. Covalent adduct formation between 16 alpha-OHE and individual histones was maximal with H1 histone. Other endogenous estrogens such as estrone, estradiol, and estriol did not interact with histones and form covalent adducts, nor did they interfere with the interaction of 16 alpha-OHE with these nuclear proteins. The evidence supports that the adduct formation between 16 alpha-OHE and histones proceeds via a stabilized Schiff base and subsequent rearrangement. This adduct formation which may have in vivo analogues may represent a mechanism for cellular transformation by this estrogen metabolite.

Estradiol↗

PubMed1988

Covalent binding of the endogenous estrogen 16 alpha-hydroxyestrone to estradiol receptor in human breast cancer cells: characterization and intranuclear localization.

The interactions of 16 alpha-hydroxyestrone (16 alpha-OHE1), a metabolite of estradiol (E2), with estrogen receptors (ERs) were compared in this study to the classic E2-receptor mechanism in human breast cancer cells MCF-7 in culture. When MCF-7 cells were incubated with radioinert 16 alpha-OHE1 or its 3H-labeled form for 4 weeks, the estrogen bound extensively and irreversibly in a time-dependent fashion to nuclear protein species that correspond to the ER. Here we show that the interactions of 16 alpha-OHE1 with the ER are different from those of E2 with the receptor. Dissociation of tritiated E2-ER or 16 alpha-OHE1-ER complexes, salt extraction, DNase and proteinase K digestion, and ethanol treatment demonstrated that the binding of 16 alpha-OHE1 to the ER corresponds to two different forms: a classical noncovalent interaction similar to that of E2, and a covalent adduct formation between the metabolite and the ER. These complexes localized preferentially in nuclear matrix components as revealed by cell fractionation and probing with a monoclonal anti-ER antibody. [3H]16 alpha-OHE1-ER complexes analyzed by polyacrylamide gel electrophoresis demonstrated a radiolabeled band at approximately 66 kDa that was absent when the exposure of cells was done in the presence of E2 in competition and that was also absent in [3H]E2 incubations. The present results when considered together with our previous findings of elevated activities of estrogen 16 alpha-hydroxylase, the enzyme responsible for the formation of 16 alpha-OHE1, in breast cancer patients and in women at enhanced risk for the disease, suggest that covalent modification of the ER may be one mechanism of malignant transformation in estrogen target tissues.

Antibodies, Monoclonal↗

PubMed1992

Induction by estrogen metabolite 16 alpha-hydroxyestrone of genotoxic damage and aberrant proliferation in mouse mammary epithelial cells.

BACKGROUND: Estrogens are potent mammary tumor promoters influencing post-initiation events via epigenetic mechanisms. The upregulation (i.e., induction) of the C16 alpha-hydroxylation pathway during 17 beta-estradiol (E2) biotransformation has been associated with mammary cell transformation. The action of E2 metabolites on tumorigenic transformation, however, is poorly understood. PURPOSE: The newly established mammary epithelial cell line C57/MG, derived from the C57BL mouse strain, was used to examine whether E2 or its metabolites, 16-hydroxyestrone (16 alpha-OHE1) and estriol (E3), function as initiators of mammary cell transformation. METHODS: DNA repair (hydroxyurea-insensitive thymidine uptake), estrogen metabolism (3H exchange to form 3H2O), hyperproliferation (increased cell number), and acquisition of anchorage-independent growth (soft-agar colonies) were used as quantitative end points to measure the relative extent of transformation. RESULTS: Treatment of cells with 200 ng/mL 16 alpha-OHE1 resulted in a 55.2% increase in DNA repair synthesis, a 23.09% increase in proliferative activity, and a 18-fold increase in the number of soft-agar colonies, relative to the solvent controls (P less than .0001). The extent of upregulation of the three end points was similar to that induced by the genotoxic mammary carcinogen 7, 12-dimethylbenz[a]anthracene (DMBA, positive control). DMBA treatment also upregulated the ratio of 16 alpha/C2 hydroxylation of E2 leading to increased formation of 16 alpha-OHE1. E2 and E3 were not effective in upregulating these markers for transformation. CONCLUSION: These results demonstrate that in nontransformed C57/MG cells, 16 alpha-OHE1 may function as an initiator, perturbing the intermediate biomarkers for preneoplastic transformation.

Animals↗

PubMed1989

Differential effects of estradiol and 16 alpha-hydroxyestrone on pituitary and preoptic estrogen receptor regulation.

16 alpha-Hydroxyestrone (16OHE1), an endogenous metabolite of estradiol (E2), binds to the estrogen receptor (ER) with low affinity, but is estrogenic in various bioassay systems. 16OHE1 binds covalently to the ER in vitro, exhibits prolonged estrogenic bioactivity in vivo, and has been implicated in several estrogen-dependent diseases. This study examined the effects of 13 days of continuous infusion of E2 or 16OHE1 on lordotic behavior, pituitary growth, and ER regulation in the cytosolic and nuclear fractions of the pituitary and preoptic area of both sexes. Finally, simultaneous pituitary nuclear exchange assays and enzyme immunoassays were performed to search for covalent 16OHE1-ER complexes in vivo. E2 induced lordosis and pituitary growth in both sexes, while 16OHE1 was only slightly less effective. While E2 treatment increased nuclear ER concentrations 2-fold vs. control values, it decreased both cytosolic and total (cytosolic plus nuclear) ER concentrations in pituitary and preoptic area by approximately 3-fold vs. control values in both sexes by exchange assay. In contrast, 16OHE1 did not decrease total pituitary ER concentrations and only minimally decreased total preoptic ER concentrations. Simultaneous exchange assay and immunoassay of pituitary nuclear extracts demonstrated proportionate increases in ER levels in female vs. male and in E2-treated vs. 16OHE1-treated rats. The ratios of (ER enzyme immunoassay divided by ER-exchange) for each rat were similar regardless of metabolite administration. The correlation of individual measurements implied that ER localized to the nuclear fraction by either E2 or 16OHE1 retained both exchangeability and immunoassayability to similar extents, but did not support the presence of 16OHE1-ER covalent complexes. The results of this study suggest that 16OHE1 has significant estrogenic bioactivity, as manifest by its effects on lordosis and pituitary growth, but, in contrast to E2, does not decrease pituitary ER concentrations and only minimally decreases preoptic ER concentrations. This property may be important in the proposed pathogenetic action of 16OHE1 in estrogen-dependent disease.

Aging↗

PubMed1985

Increased levels of 16 alpha-hydroxyestrone-modified proteins in pregnancy and in systemic lupus erythematosus.

The ketolic estrogen 16 alpha-hydroxyestrone (16 alpha OHE) reacts with lysine residues, forming stable covalent adducts with proteins. To determine the extent of protein modification by 16 alpha OHE in vivo, we measured the level of 16 alpha OHE-lysine present within proteins of varying half-lives obtained from normal subjects, patients with systemic lupus erythematosus (SLE), and pregnant women. The latter groups have higher than normal levels of plasma 16 alpha OHE. The proteins analyzed were membrane proteins of the red cell and the lymphocyte and basement membrane proteins of the glomerulus. We report that elevated levels of plasma 16 alpha OHE led to increased formation of 16 alpha OHE-protein adducts and that the level of these adducts increases with the half-life of the protein. In the case of erythrocyte membrane proteins, pregnant women and women with SLE had significantly higher mean levels of 16 alpha OHE-lysine than normal women (normal, 5.2 pmol 16 alpha OHE-lysine/mmol leucine; SLE, 15.7; pregnant, 24.9). A similar elevation in the modification of lymphocyte proteins in women was found (normal, 15.6; SLE, 40.5). Since the degree of protein modification also was dependent on the ambient level of free 16 alpha OHE, these measurements provide a useful indicator of the long term 16 alpha OHE status of an individual. The modification of proteins by 16 alpha OHE may be a link in the relationship between female hormones, pregnancy, and systemic lupus erythematosus.

Adolescent↗

PubMed1986

[Determination of serum 16 alpha-hydroxydehydroepiandrosterone, 16 alpha-hydroxyestrone and estriol by gas chromatography-mass spectrometry and their perinatal movement].

In order to study the mechanism of estriol (E3) formation in the fetoplacental unit, a method for determining E3 and its precursors, 16 alpha-hydroxydehydroepiandrosterone (16 alpha-OH DHA) and 16 alpha-hydroxyestrone (16 alpha-OH E1) in blood using Gas Chromatography-Mass Spectrometry (GC-MS) was newly developed. Deuterium labelled steroids, 3.4.4.-d3-16 alpha-OH DHA 2.4.17.-d3-E2 and 2.4.-d2-E3 were synthesized and used as the internal standards. After removal of free steroids with ether, the residue was solvolyzed and extracted with ethyl acetate as free form. Steroids were analysed after the formation of T.M.S. and T.F.A. derivative. The values for each steroid in maternal peripheral vein blood (M.V.), umbilical artery blood (U.A.) and vein blood (U.V.) were studied. Conjugated steroid values in M.V. obtained at normal vaginal delivery (13 cases) were as follows: 16 alpha-OH DHA 230.3 +/- 76.3 ng/ml, 16 alpha-OH E1 19.34 +/- 7.00 ng/ml and E3 158.8 +/- 50.2 ng/ml (mean +/- S.D.), respectively. The levels of these three steroids in cord blood were significantly higher than those in maternal blood. These results show that the steroids are actively produced in the fetoplacental unit. A significant increase in all the steroids was associated with labor. None of the values for E3 precursors in umbilical blood correlated with that of conjugated E3 in maternal blood. The significance of 16 alpha-OH DHA and 16 alpha-OH E1 as intermediates of E3 formation in the fetoplacental unit is discussed.

Dehydroepiandrosterone↗

PubMed1985

[Studies on RIA of 16 alpha-hydroxyestrone and its clinical application].

UNLABELLED: 16 alpha-hydroxyestrone (16 alpha-OH-E1) is an important intermediary metabolite in the biosynthetic pathway leading to estriol. No established routine method has been published to measure this steroid in the organism. A new RIA 16 alpha-OH-E1 method was developed and by using this method some interesting clinical data were obtained. METHOD: Rabbits were immunized with 16 alpha-OH-E1-3-CME-BSA to produce its antiserum. 16 alpha-OH-E1-3H was synthesized by incubating estrone-3H with the human fetal liver preparation and NADPH. As samples, peripheral blood of pregnant women, umbilical artery blood (UA), umbilical vein blood (UV) and amniotic fluid were collected. To each sample, 1000 dpm of 16 alpha-OH-E1-3H was added as a tracer, extracted with ether, and the extract was separated on TLC and LH-20. The 16 alpha-OH-E1 fraction was collected and used for RIA. RESULTS: The 16 alpha-OH-E1 levels (ng/ml) in peripheral maternal blood of normal gestation before 11 weeks, 12-23 weeks, 24-36 weeks and after 37 weeks were 0.98 +/- 0.07 (mean +/- S.E.), 2.42 +/- 0.30, 4.76 +/- 0.42 and 5.49 +/- 0.98, respectively. A significant increase in the steroid titer was observed as gestational weeks advanced.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗